I love the sound of a V7sus4 chord in a strummy singer-songwriter-style song. The formula is 1 4 5 b7, e.g G C D F in the key of G Here are all the open position 7sus4 chords I can think of.
A7sus4 (key of D): x02030
B7sus4 (key of E): x24200 - my favourite!
C7sus4 (key of F): x3x066
C7#sus4 (key of F#): x46x02 - if it's too much of a stretch, you can get away with x44x04
D7sus4 (key of G): xx0213
E7sus4 (key of A): 020230 or 022230
F#7sus4 (key of B ): 244400 or 244600 or 244x00 or 242x00
G7sus4 (key of C): 3x0011
What are your favourite open position 7sus4 chords?